Operation Wigwam | |
---|---|
Information | |
Country | United States |
Test site | Pacific Ocean off California |
Period | 1955 |
Number of tests | 1 |
Test type | Underwater |
Max. yield | 30 kilotonnes of TNT (130 TJ) |
Test series chronology | |
Operation Wigwam [1] involved a single test of the Mark 90 "Betty" nuclear bomb. It was conducted between Operation Teapot and Project 56 on May 14, 1955, about 500 miles (800 km) southwest of San Diego, California. 6,800 personnel aboard 30 ships were involved in Wigwam. The purpose of Wigwam was to determine the vulnerability of submarines to deeply detonated nuclear weapons, and to evaluate the feasibility of using such weapons in a combat situation. [2] The task force commander, Admiral John Sylvester, was embarked on the task force flagship USS Mount McKinley. Wigwam was the first atomic test in the deep ocean, and it remains the only test that has been conducted in water deeper than 1,000 ft (300 m). [3] [4]
The test device was suspended to a depth of 2,000 feet (610 m) by cable attached to a barge. A 6-mile (9.7 km) tow line connected the 205-foot (62 m) Cherokee-class fleet tug, USS Tawasa, to the shot barge. Suspended from the tow lines of other tugs were three miniature unmanned target submarines designated "SQUAWS", each packed with cameras and telemetry instruments. Those targets were 132 ft 2.625 in (40.3 m) long, 4/5 scale of the SS-563 prototype hull (USS Tang (SS-563)) to assess effects of the explosion on a submarine hull. [2]
The time of detonation was 1300 hrs local Pacific Time (noon Pacific Standard Time). [2]
The equipment intended for direct measurement of the explosion-generated underwater bubble was not operational at the time of the shot, but based on other measurements, the bubble's maximum radius was calculated as 376 feet (115 m), and its pulsation period approximately 2.83 seconds. [5]
See also the table at List of United States' nuclear weapons tests.
The underwater sound from the Wigwam explosion was recorded on bottom-mounted hydrophones at Point Sur and Point Arena off California, and at Kāneʻohe Bay off Oahu, Hawaii. [3] The sound emanating from the explosive test began as an intense water shock wave. As the sound traveled away from the test point, it reflected from topographic features, such as islands and seamounts, located throughout both the North and South Pacific Basins. The reflected sound was then recorded as hours-long coda at Kaneohe and Point Sur. [3] [4] Some of the acoustic energy travelled round trip distances of over 12,000 miles (20,000 km). The sound signals provided one of the early measurements of underwater sound attenuation at low frequencies. [3]
The detonations in the United States' Wigwam series are listed below:
Name [note 1] | Date time (UT) | Local time zone [note 2] [6] | Location [note 3] | Elevation + height [note 4] | Delivery, [note 5] Purpose [note 6] | Device [note 7] | Yield [note 8] | Fallout [note 9] | References | Notes |
---|---|---|---|---|---|---|---|---|---|---|
Wigwam | May 14, 1955 20:00:00.0 | PST (−8 hrs) | Pacific Ocean off California 28°44′00″N126°16′00″W / 28.7333°N 126.2667°W | 0–610 m (2,000 ft) | underwater, weapon effect | Mk-90 B7 "Betty" depth bomb | 30 kt | [1] [7] [8] | Deep water submarine hull test, including nuclear depth bomb, to gauge surface contamination. Used instrumented "squaws", subscale sub pressure hulls. Tested shielded warships with base surge. |
Operation Tinderbox was a series of 14 nuclear tests conducted by the United States in 1979–1980 at the Nevada Test Site. These tests followed the Operation Quicksilver series and preceded the Operation Guardian series.
Operation Guardian was a series of 14 nuclear tests conducted by the United States in 1980–1981 at the Nevada Test Site. These tests followed the Operation Tinderbox series and preceded the Operation Praetorian series.
Operation Storax was a series of 47 nuclear tests conducted by the United States in 1962–1963 at the Nevada Test Site. These tests followed the Operation Fishbowl series and preceded the Operation Roller Coaster series.
Operation Latchkey was a series of 38 nuclear tests conducted by the United States in 1966–1967 at the Nevada Test Site. These tests followed the Operation Flintlock series and preceded the Operation Crosstie series.
The United States's Bowline nuclear test series was a group of 47 nuclear tests conducted in 1968–1969. These tests followed the Operation Crosstie series and preceded the Operation Mandrel series.
Operation Quicksilver was a series of 16 nuclear tests conducted by the United States in 1978–1979 at the Nevada Test Site. These tests followed the Operation Cresset series and preceded the Operation Tinderbox series.
Operation Hardtack II was a series of 37 nuclear tests conducted by the United States in 1958 at the Nevada Test Site. These tests followed the Operation Argus series and preceded the Operation Nougat series.
Operation Tumbler–Snapper was a series of nuclear weapons tests conducted by the United States in early 1952 at the Nevada Test Site. The Tumbler–Snapper series of tests followed Operation Buster–Jangle and preceded Operation Ivy.
Operation Sunbeam was a series of four nuclear tests conducted at the United States's Nevada Test Site in 1962. Operation Sunbeam tested tactical nuclear warheads; the most notable was the Davy Crockett.
The United States's Praetorian nuclear test series was a group of 19 nuclear tests conducted in 1981–1982. These tests followed the Operation Guardian series and preceded the Operation Phalanx series.
Operation Charioteer was a series of 16 nuclear tests conducted by the United States in 1985–1986 at the Nevada Test Site. These tests followed the Operation Grenadier series and preceded the Operation Musketeer series.
The United States's Musketeer nuclear test series was a group of 14 nuclear tests conducted in 1986–1987. These tests followed the Operation Charioteer series and preceded the Operation Touchstone series.
The United States's Touchstone nuclear test series was a group of 13 nuclear tests conducted in 1987–1988. These tests followed the Operation Musketeer series and preceded the Operation Cornerstone series.
The United States's Sculpin nuclear test series was a group of 7 nuclear tests conducted between October 1990 and September 1991. These tests followed the Operation Aqueduct series and preceded the Operation Julin series.
The United States's Grommet nuclear test series was a group of 34 nuclear tests conducted in 1971–1972. These tests followed the Operation Emery series and preceded the Operation Toggle series.
Operation Roller Coaster was a series of four nuclear tests conducted jointly by the United States and the United Kingdom in 1963, at the Nevada Test Site. The tests did not involve the detonation of any nuclear weapons. Instead, their purpose was to evaluate the distribution of radioactive particles in a "dirty bomb" scenario, or an inadvertent, non-nuclear detonation of a nuclear weapon, as well as to evaluate the effectiveness of storage structures in containing the explosion and the particles released. The tests followed the Operation Storax series and preceded the Operation Niblick series.
Operation Project 56 was a series of 4 nuclear tests conducted by the United States in 1955–1956 at the Nevada Test Site. These tests followed the Operation Wigwam series and preceded the Operation Redwing series.
Operation Project 58/58A was a series of 4 nuclear tests conducted by the United States in 1957–1958 at the Nevada Test Site. These tests followed the Operation Plumbbob series and preceded the Operation Hardtack I series.